Push button switch with leaf spring contacts



Jan. 5, 1965 R. H. FINK 3,164,707

PUSH BUTTON SWITCH WITH LEAF SPRING CONTACTS Filed July 18. 1961 l vv l l- FIGA 'liill TIC I I l 4| 35 \\y|r\\ INvENToR. noel-:R H. FI NK AGENT United States Patent 3,164,707 PUSH BUTTON SWITCH WITH LEAF SPRING CUNTACTS Roger H. Fink, Lancaster, Ohio, assignor to Essex Wire Corporation, Fort Wayne, Ind., a corporation of Michigan Filed July 1S, 1961, Ser. No. 124,983 2 Claims. (Cl. 20u-159) This invention relates to a push button switch lfor selectively opening and closing an electric circuit and more particularly to improvements in push button switches having a pair of resilient contact arms and a movable contact movable into and out of bridging engagement with the contact arms.

An object of the invention is to provide an improved push button switch of the foregoing character that is of simple design with .a minimum number of parts which may be manufactured at low oost.

Another object of the invention is to provide a push button switch of the forego-ing character with an improved arrangement of the resilient contact arms which insures a reliable engagement therewith by the bridging contact.

For a more complete understanding of the invention, reference may be had to .the following description taken in connection with the accompanying drawing in which;

FIG. 1 is a view in elevation of the front end of a push button switch embodying the invention;

FIG. 2 is a View partly in section taken on line 2 2 of FIG. l; Y

FIG. 3 is a View in section similar to FIG. 2- showing additional details of construction of the switch;

- FIG. 4 is a view in section taken on line 4-4 of FIG l;

FIG. 5 is a view in section similar to FIG. 4 showing the switch in the olf position;

FIG. 6 is a view in elevation of the rear end of the switch; and

FIG. 7 is an end view of an insulator and contact assembly prior to assembly in the switch housing.

Referring to the drawing, the push button switch embodying the invention is shown in FIG. 5 mounted in a supporting panel 10 for oper-ation by a movable door 11 or the like. The switch is formed from seven parts cornprising a hollow housing 12 of resilient .insulation material such as nylon, an insulator 13 of molded insulation material frictionally held in the rear end of the housing 12, a pair of iden-tical contact members 14 and 15 frictionally secured on the insulator 13, a flat bridging contact 16 formed of sheet metal that extends into the insulator 13, a push button 17 of molded'insulation material disposed lin the front end of the housing 12 and extending therefrom, and a coil spring 18 confined ybetween the inner end ofthe insulator 13 and the bridging contact 16 so as to force the push button outwardly. While in the switch illustrated the contact 16 engages both contact members 14 and in the outward position of the push button 17 to complete anelectric circuit therebetween, it will be apparent that the switch may be modified for causing engagement of the Contact 16 with the contact members 14 and 15 in the inward position of the push button 17.

The housing 12 has a cylindrical side wall 19 closed atits front end by an end wall 20 which is provided with a central hole 21. An annular flange 22 extending outwardly of the `front end of the side wall Y19 is provided with a peripheral series of spring fingers 23 for snapping engagement in an opening of panel 10. The inner surface of the housing side wall 19 is formed with a circumferential recess 24 near the rear end. The inner surface of wall 19 is also enlarged at the rear end of the housing 12 to provide an internal circumferential rib 25.

The open rear end of the housing 12 receives the insulator 13. The insulator 13 has two generally cylindrical ice portions 26 and 27 of generally different diameters. The

outer surface of the portion 26 is formed with two longi-` tudinally extending recesses 28 and 29 which provide oppositely disposed projections 30 and 31. Protruding from the projections 30 and 31 are bead portions 32 shaped to conform generally with the shape of recess 24. The overall diameter of the ybead portions 32 should be slightly less than the diameter of the inner surface of recess 24 while the overall diameter of projections 30 and 31 should be slightly less than the diameter of .the inner surface of housing wall'19. It will be seen that the insulator 13 is secured in place in the housing 12 by pushing the insulator 13 into the rear open end of the housing 12 until the bead portions 32 snap over the rib 25 into recess 24.

The reduced diameter portion 27 is divided in two by a longitudinally extending gap 33 having two notch portions 34 comprising extensions of a central slot 35 passing through .the insulator portion 26 and serving as a guide yfor the bridging contact 16. The gap 33 also is in communication with the, two recesses 28 and 29. The recesses 28 and 29 are each shaped to have a section of reduced width by providing rectangular protuberances 36 which extend into the recesses 28 and 29.

The contact members 14 and 15, respectively, are positioned in the recesses 28 and 29 of insulator 13. Each of the contact members 14 and 15 comprisesan elongated strip of metal fashioned at one end to form inwardly bowed yieldable contact-engaging portions 37 which ex tend into gap 33 of the insulator portion 27. Below the contact-engaging portion 37 of eachcontact member is a wider terminal portion 38 having an outwardly projecting dimple 39 and a pair of side anges 40. The terminal portions 38 are fashioned to be slightly wider than the width of recesses 28 and 29 so as to have an interference lit therewith when forced into the recesses to prevent separation. 'Ille side ilanges 40 further cooperate with protuberances 36 to prevent longitudinal movement of the contact members 14 and 15. The dimple 39 of each contact member 14 and 15 and the rib 25 of the housing side wall 19 cooperate to resiliently hold a bullet-type connector 41 which may be inserted in each of the recesses 28 and 29 as illustrated in FIG. 5.

The pushbutton 17 is slidably mounted in hole 21 of the housing end wall 20 and includes an enlarged inner end 42 which limits outward movement of the push button 17. The inner end 42 of the push button 17 is formedvwith a generally cone-shaped recess 43 in which is seated the similarly shaped end 44 of the bridging contact 16. The latter has two side arms 45 engaged by one end of the coilspring 18, the other end'of which surrounds `the insulator portion 27 and engages the end surface of the insulator portion 26. Extending toward and into insulator 13 is the L-shaped contact portion 46 of bridging contact 16. Contact portion 46 includes a stem 47 arranged in parallel relation to the axis of the housing 12 and constantly engaged by the contact-engaging portion 37 of contact member Y15. The stem 47 of bridging contact 16 is provided with a laterally disposed extension 48 which engages the Contact member 14only in the outward position of the push button 17. The stem 47 and its extension 48 lie in the same plane and have a sliding lit with notches 34 and slot 35 to guide the bridging contact 16 in straight line axial movements with respect to the housing 12. The opposite end 44 of contact 16 is axially centered with respect to the housing 12 by virtue of its iit with the recess 43 in the push button 17.

It is to be noted that according to a feature of this invention the two conact members 14 and 15 are arranged with their contact-engaging portions 37 laterally spaced `from each other. Referring particularly to FIG. 7 which shows the members 14 and 15 secured to the insulator 13 prior to the latter being assemblied in the housing 12,

it will be seen that major parts of the contacts t4 and 15 are dipsosed on opposite sides of the plane through which bridging contact 16 moves, but are biased so that projecting part 49 of each contactengaging portion 37 extends beyond this plane. ln assembly of the switoh parts the projecting part 49 of contact 1S` is displaced outwardly to bear against stem 47 of the briding contact 16 at all times'.k The projecting part 49 of contact member 14, however, remains in its normal biased position except when the push button 17 is released to move to the position shown in FIG. 4. As the coil spring t8 moves the push button 117` outwardly the edge of the extension 48 of bridging Contact 16 comes into engagement with t the contact-engaging portion 37 of contact member i4 which will iiex outwardly until Vthe projecting part 49 engages the side of the extension 48 of bridging contact 16. This eiects a good wiping action between the contact member 14 and the bridging contact t6 without any likelihood of overstressing or damaging the contact member t4. The other contact member l remains constantly in engagement with the bridging contact 16 and thus the contactengagement of these parts is never adversely affected by sparking resulting from interruption of the circuit through the switch.

It will be apparent that if it is desired to bias contact members 14 and l5 to a greater extent than that illustrated in the drawing, it may be desirable to provide stops in the gap 33 for limiting the inward iexing of the contact portions 37. Such stops obviously could be formed integrally with the portion 26 of insulator 13. n

While the invention has been illustrated and described in its preferred embodiment and has included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described, sinee the same may be carried out in other Ways falling within the scope of the invention as claimed.

What is claimed is:

1. In an electric switch, the combination of:

(a) a hollow housing having a front end and a rear end;

(b) a push button operator disposed within said housing and having a portion extending out of the front end of said housing;

(c) a bridging contact of sheet metal having a at contact portion disposed within said housing and axially shiftable with said operator;

(d) means within said housing for guiding movement of said contact portion along a single plane coextensive with the plane of said .contact portion;

(e) spring means Within said housing urging said inner end of said operator and said bridging contact away from the rear end of said housing;

(f) a pair of spaced, elongated, stationary spring contact members having front and rear portions, the rear portions of said contact members being mounted at the rear end of said housing on opposite sides of said single plane, the front portions of said contact members extending in spaced relation toward the front end of said housing for resilient'bridging engagement with the contact portion of said bridging contact;

(g) each front portion of said contact members comprising a iirst generally at portion inclining forwardly and inwardly toward said single plane from said rear portion and a second generally liat portion inclining forwardly and outwardly of said single plane from said irst portion of the respective contact memberfon the same side of said single plane as said rst portion of 4the respective contact member, said first portions inclining in opposite directions and said second portions inclining in opposite directions, and said front portions being `offset laterally and having portions crossed and aligned relative to each other in a direction lengthwise of the contact portion of said bridging contact to be tensioned vby engagementyof the latter therebetween.

2. In an electric switch, the combination of:

(a) a hollow switch housing formed of insulating mate-v rial and having front and rear portions; 1

(b) a push button operator slidably mounted within said housing and having an end portion extending out n of the front end of said housing;

(C) an insulator secured in the rear end of said housing and provided with a central longitudinal slot therein;

(d) a bridging contact of sheet metal disposed within said housing and including a flat contact portion cornprising a stem portion and a laterally `disposed extension portion, said bridging contact being guided in said slot for movement in a single plane and axially shiftable with said operator;

(e) spring means engaging said insulator and urging said operator and said bridging contact away from the rear end of said housing;

(f) a pair of spaced, elongated, stationary spring contact members having vfront and Irear portions,-the rear portions of said Contact members being secured to said insulator on opposite sides of said slot, the front portions of said contact members extending in spaced relation toward the front end of said houisng for resilient bridging switching engagement with the contact portion of said'bnidging contact;

(g) each front portion of said contact members comprising a irst generally at port-ion inclining forwardly andinwardly toward said plane from said rear portion and a second generally flat portion inclining forwardly and outwardly of said plane from said iirst portion of the respective contact member kon the same side of said plane as said iirst portion of the respective Contact member, said first portions inclining in opposite directions and said second portions inclining in opposite directions, said front portions being oset laterally and having portions crossed and aligned relative to each other in a direction lengthwise of said extension portionof said bridging contact;

(h) the front portion of one of said contactivmembers at the junction` of said first and second portions thereof engaging one side of said stem portion of saidbridging contact in all positions of said bridging contact, the front portion of the other of said contact members at the junction of said irst and second portions thereof engaging said extension portion of said bridging Contact on the oppositevside thereof when said bridging contact is in a predetermined position and disengaging from said bridging Contact upon movement thereof from said predetermined position, said front portions of said contact members being tensioned byengagement with said bridging contact to assure a good wiping action and good contact pressure of said contact members with said bridging contact.

References Cited in the iile of this patent UNTTED STATES PATENTS 

1. IN AN ELECTRIC SWITCH, THE COMBINATION OF: (A) A HOLLOW HOUSING HAVING A FRONT END AND A REAR END; (B) A PUSH BUTTON OPERATOR DISPOSED WITHIN SAID HOUSING AND HAVING A PORTION EXTENDING OUT OF THE FRONT END OF SAID HOUSING; (C) AND BRIDGING CONTACT OF SHEET METAL HAVING A FLAT CONTACT PORTION DISPOSED WITHIN SAID HOUSING AND AXIALLY SHIFTABLE WITH SAID OPERATOR; (D) MEANS WITHIN SAID HOUSING FOR GUIDING MOVEMENT OF SAID CONTACT PORTION ALONG A SINGLE PLANE COEXTENSIVE WITH THE PLANE OF SAID CONTACT PORTION; (E) SPRING MEANS WITHIN SAID HOUSING URGING SAID INNER END OF SAID OPERATOR AND SAID HOUSING; FROM THE REAR END OF SAID HOUSING; (F) A PAIR OF SPACED, ELONGATED, STATIONARY SPRING CONTACT MEMBERS HAVING FRONT AND REAR PORTIONS, THE REAR PORTIONS OF SAID CONTACT MEMBERS BEING MOUNTED AT THE REAR END OF SAID HOUSING ON OPPOSITE SIDES OF SAID SINGLE PLANE, THE FRONT PORTIONS OF SAID CONTACT MEMBERS EXTENDING IN SPACED RELATION TOWARD THE FRONT END OF SAID HOUSING FOR RESILIENT BRIDGING ENGAGEMENT WITH THE CONTACT PORTION OF SAID BRIDGING CONTACT; (G) EACH FRONT PORTION OF SAID CONTACT MEMBERS COMPRISING A FIRST GENERALLY FLAT PORTION INCLINING FORWARDLY AND INWARDLY TOWARD SAID SINGLE PLANE FROM SAID REAR PORTION AND A SECOND GENERALLY FLAT PORTION INCLINING FORWARDLY AND OUTWARDLY OF SAID SINGLE PLANE FROM SAID FIRST PORTION OF THE RESPECTIVE CONTACT MEMBER ON THE SAME SIDE OF SAID SINGLE PLANE AS SAID FIRST PORTION OF THE RESPECTIVE CONTACT MEMBER, SAID FIRST PORTIONS INCLINING IN OPPOSITE DIRECTIONS AND SAID SECOND PORTIONS INCLINING IN OPPOSITE DIRECTIONS, AND SAID FRONT PORTIONS BEING OFFSET LATERALLY AND HAVING PORTIONS CROSSED AND ALIGNED RELATIVE TO EACH OTHER IN A DIRECTION LENGTHWISE OF THE CONTACT PORTION OF SAID BRIDGING CONTACT TO BE TENSIONED BY ENGAGEMENT OF THE LATTER THEREBETWEEN. 